"The country through which the Onondaga Salt Group extends, is usually marked by a series of low, gravelly hills, and clayey valleys, on which a stunted growth of timber prevails, known by the name of 'Oak Openings.' Small portions of sulphate of strontia, galena, and blende, with rhomb spar, occur in the upper portion of the group. Gypsum and salt are, however, the only minerals of economical value: of the former many thousand tons are excavated. Several acidulous springs issuing from these deposits, have been found to contain free sulphuric acid."—D. D. Owen's Review of the N. Y. Geological Reports.
Jules Marcou, in his Geology of the United States, places the northern portion of the southern peninsula of Michigan in the Terrain Devonian.
Report of J. S. Dixon and others, on Grand Traverse Bay, p. 523, in Michigan Agricultural Reports for 1834, says:
"The atmosphere is moist and wholesome—no disease, and healthy as any portion of country. It is a well established fact, that water cools first on the surface, then sinks while the warm water rises, and consequently ice never forms till the whole body of water has been cooled to thirty degrees. Now, from this fact, the philosopher will at once deduce the climate of this region. Traverse Bay is from one hundred to nine hundred feet deep and the water never cools to thirty-two degrees till the middle of February, and in Lake Michigan in the middle never, and so long as the water in these continuous reservoirs is warmer than the air, the former must obviously warm the latter.
"It is accordingly well known that in England, on the east side of the Atlantic 7° or 8° farther north than Traverse Bay, the climate, as it regards cold in winter, is about equal to that of Washington City, and so it is on the east side of the Pacific ocean, in Oregon. Hence it is evident that the seasons on the east side of Lake Michigan must be uniform.
"Around Traverse Bay the frost seldom kills vegetables till in November, and seldom occurs in spring later than the 1st of May. In November it gets cold enough to freeze. The vapors arising from the lake and bay fall in snow and cover the ground before the frost has penetrated it at all; it accumulates several months till it is two feet deep, sometimes deeper, and remains till April; and when it goes off; cattle find enough to eat in the woods. This region is much more sunny between the middle of March and December than southern Michigan, and every vegetable physiologist will at once state that the influence of this on vegetation must be very great, and accordingly spring crops grow with such rapidity that corn is fit to be cut by the 1st of September. From December to March, as above, the atmosphere is hazy, cloudy, and frosty, though the thermometer never sinks so low as in the south of Michigan by ten or twelve degrees (8 or 10 degrees below zero, being the lowest yet known), and a winter thaw is unknown here. Hence we never have mud in winter, and but little at any season.
"With the very defective cultivation hitherto used here, yield of crops are as follows:—Potatoes, free of rot, 150 to 300 bushels to the acre; oats 25 to 60; corn 25 to 50; wheat (spring) the largest yet raised 27 bushels. Wheat raised here is much more plump than in southern Michigan, and there is no instance of its being smothered or injured by snow, because the snow never thaws and alternately freezes into a hard crust, or ice, so as to exclude the air from the wheat, as in other places.
"We confidently predict that this will become the most prolific wheat region in the west; rust and insects are unknown. All experience goes to prove that this will be a great fruit country. The Indian apple and peach trees, although few in number bear well every year; and as to wild blackberries and raspberries, both as to size and flavor, there is absolutely no end. They serve all the inhabitants and millions of pigeons for several months."
United States census, 1850, shows products of States.